Subsurface well tool



Oct. 3, 1961 J. R. BAKER ETAL SUBSURFACE WELL TOOL 3 Sheets-Sheet 2 Filed Dec. 25, 1957 INVENTORS. CI-OHM R, BQKEE DHA/ C, PRESTON, rife.

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SUBSURFACE WELL TOOL Filed Dec. 25, 1957 3 Sheets-Sheet 3 3,002,561 SUBSURFACE WELL TOOL John R. Baker, Pasadena, and Dan C. Preston, In, Whittier, Califl, assignors to Baker Oil Tools, Inc., Los An- .geles, Calif, a corporation of California Filed Dec. 23, 1%7, Ser. No. 704,602 16 Claims. (Cl. 166120) The present invention relates to subsurface well bore equipment, and more particularly to well packers, and the like, adapted to be set in a well casing, or similar conduit string, disposed in a well bore. An object of the present invention is to provide an improved well packer adapted to be run in a well bore on a tubular string and anchored in packed-oil condition therewithin, the tubular string remaining in the well bore in proper relation to the packer to conduct fluid between the well formation below the setting location of the packer and the top of the well bore.

Another object of the invention is to provide a well packer adapted to be run in the well bore on a tubular string and anchored in packed-oft condition therewithin, at least partially by the application of hydraulic pressure to parts of the packer, which pressure is transmitted through the fluid in the tubular string, there being an absence of communication between the hydraulically actuated parts of the packer and the interior of the tubular string after the packer has been set in the well bore.

A further object of the invention is to provide a well tool having slips for anchoring the tool in a well bore and embodying an improved device for preventing premature setting of the slips while the tool is being run in the well bore.

An additional objection of the invention is to provide an improved releasable coupling or connection between a well packer and a tubular string by which the packer is run in a well bore.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

' Referring to the drawings:

FIGURE 1 is a combined sideelevation'al view and longitudinal section through .a well packer and setting tool combination, with the parts related for running the equipment in a well casing;

FIG. 2 is an enlarged, fragmentary longitudinal section of a portion of the well packer shown in FIG. 1;

FIG. 3 is a longitudinal section through the apparatus disclosed in FIG. 1, with the lower slips in anchored condition; 7

FIG. 4 is a view similar to FIG. 3, illustrating the well packer after it has been almost fully set in the well casing;

FIG. 5 is a view similar to FIG. 3 illustrating the well packer fully anchored in packed-off condition in the well casing, with the tubular running-in string disconnected therefrom;

FIG. 6 is an enlarged, fragmentary longitudinal section of a portion of the well packer, illustrating the device for preventing premature setting of the slips while the tool is being run in the well casing; FIG. 7 is a view similar to FIG. 6, with the prematur setting device in released condition.

As disclosed in the drawings, a well packer A is to be run in a well casing B on the lower portion of a tubular string C, such as tubing or drill pipe, extending to the top of the well bore, and is to be anchored in packed-off condition in the well casing after its setting location has been reached. After having been fully set in the well casing, the apparatus can be conditioned for conducting well production from below the well packer A to the top of the hole. Conversely, fluid could also be pumped down the tubing string for injection into the formation below the well packer. I

The well packer A includes a tubular body 15} having an enlarged head 11 at its upper portion, provided with a threaded box 12, the threads preferably being lefthand. To the lower portion of the body is threadedly secured a body cylinder 13 having an upwardly extending sleeve portion ld'spaced from the periphery of the body to define an annular cylinder space 15 therebetween in which an annular piston 16 is disposed. Leakage of fluid from the cylinder space 15 along the piston 16 is prevented by an outer side seal 17 on the piston slidably engaging the inner wall 18 of the cylinder sleeve, and by an inner side seal 19 on the piston slidably and sealingly engaging the periphery 2d of the body. Fluid can enter the cylinder space 15 from the interior of the body, or body passage 21, through one or a plurality of sideports 22.

Disposed around the body 10 is a plurality of circurriferentially spaced segmental lower slips 23 which are adapted to anchor the well packer to the well casing against downward movement therewithin. vThese slips may rest initially on the upper end 24 of the cylinder sleeve 14 and are retained in retracted position by shear screws 25 securing these slips'to a lower expander 26 slidably mounted on the body. Initially, such expander is prevented from moving relatively to the body ill by one or a plurality of shear screws 27 securing the lower expander to the body. The lower expander 26 has a downwardly and inwardly converging external tapered surface 28 engageable with companion inner tapered surfaces 29 in the lower slips, so that relative upward 1 movement of the slips with respect to the expander will effect a radial outward shifting of the slips 23 into engagement with the wall of the well casing B.

A packing sleeve 30 of rubber or rubber-like material surrounds the body, with its lower end engaging the upper end of the lower expander 26. The upper end of the packing sleeve engages an upper expander 31 which is initially secured to the body of the tool by one or more shear screws 32. This upper expander has an upwardly converging tapered expander surface 33 engageable with companion inner tapered surfaces 34 on an upper set of segmental slips 35 surrounding the body, these slips being held initially in retracted position by shear screws 36 securing them to the upper expander 31. When the upper slips move downwardly relative to the upper expander they are shifted radially outward into engagement with the well casing, as explained hereinbelow. The upper slips 35 are secured to a setting sleeve 37 surrounding the body and extending upwardly along its head 11, preferably terminating a substantial distance above the upper end 38 of the body head. The connection between the setting sleeve 37 and slips 35 is designed to prevent their relative longitudinal movement, but permits radial move- .ment of the slips with respect to the setting sleeve. As disvent longitudinal movement of the setting sleeve 37 relative to the slips at this time.

For the purpose of preventing relative rotation between the body of the tool and. the parts surrounding it, a slidable spline connection is provided between the body and the upper expander 31. Thus, the body has a longitudinally extending keyway 41 receiving a key 42 which fits within a longitudinal groove 43 in the upper expander. Moreover, for the purpose of permitting upward movement of the body 10 relative to the parts surrounding, it, but to preclude relative downward movement of the body with respect to the setting sleeve 37 and the upper slips and upper expander 31, a one-way clutch or racthet device is disposed between the body and the setting sleeve. As shown most clearly in FIG. 2', such one-way device inpludes downwardly facing circumferential ratchet teeth 44 on the body it coacting with companion upwardly facing teeth 45 on the inner portion of a split ratchet sleeve 46 surrounding the body. The exterior of the ratchet sleeve has circumferential cam members 47 thereon adapted to coact with. companion cam members 48 on the interior of the setting sleeve 37. The body 10 can move upwardly relative to the ratchet sleeve 46, the ratchet sleeve merely expanding and the body teeth. 44 ratcheting freely in an upward direction over the inner ratchet teeth 45 on the sleeve 46. However, downward movement of the body 10 will cause the ratchet teeth 44, 45 to coengage, the downward force being transmitted to the setting sleeve 37 through the cam elements 47, 43, which have coengaging inclined surfaces 49 tending. to earn the sleeve 46 inwardly and. retain the ratchet teeth in engagement with one another. Thus, downward movement of the body It! is transmitted to the setting .sleeve 37. If desired, the ratchet sleeve 46 may at first be secured to the body 10 by one or more shear screws 50 which. will. become disrupted upon thetaking 0t sufll- .cient upward strain on the body 1t).

' For the purpose of preventing premature disruption of the screws 25 holding the lower slips 23 to the lower ex pander 26 and effecting outward expansion of thelower slips against the well casing, as during lowering of the apparatus A in the well casing 15', a device is provided between the lower slips and body (see FIGS. 6 and 7.). This device includes a stop ring 51 disposed within a circumferential inner groove 52 in the lower slips, thestopring being split with its inner portion disposed initially within a circumferential groove 53 in the body 1d of the tool. The lower, inner portion 54 of the stop ring is tapered in an upward and inward direction, this surface being engaged by a companion tapered surface 55 on a solid trip ring 56 disposed on the body and initially secured there'- to by one or more shear pins or screws 57. This trip ring 56 extends below the lower ends 58 of the slips 23 and into the cylinder space 15 between the cylinder sleeve 14 and body 10, and is adapted to be engaged by the upper end 59 of the annular piston 16 when the piston is moved upwardly hydraulically for the purpose of. setting the lower slips 23 against the well casing. B, as described hereinbelow.

Although forming no part of the present invention, the well packer A illustrated has a feeler andjunlc pusher 69 secured to the lower end of the body cylinder '13 by screws 61, or the like, and also is provided with a flapper valve member 62 pivotally mounted on the lower portion. of the body cylinder 13, this flapper valve member being movable upwardly by a spring 63 into sealing engagement with a valve seat 64 on. the lower portion of the body cylinder.

Setting of the well packer A in. the well casing B is initiated hydraulically by the application of pressure to the fluid in the tubing string. C and the interior of the packer itself. The lower portion of the tubular string C is threadedly secured to an upper sub 65 threadedly attached to the upper end of a setting. mandrel 66 made in several sections. The setting mandrel includes an upper section 67, threadedly secured to a lower section 68, the mandrel being disposed in the body passage 21 to a point below the body ports 22. The mandrel has a suitable side seal 69 adapted to seal against the inner wall of the body 10 above the body ports 22-, and also with a suitable lower side seal 70- adapted to sealingly engage the inner wall of the body below the body ports 22. Between the seals, the mandrel 66- has a one or a plurality of side ports 71 to establish fluid communication between the cylinder space 15 and the interior of the" mandrel and the tubular string C thereabove, the fluid passing through the body ports 22 into the cylinder 13 for action upon the annular piston 16.

The tubular mandrel 66 is detachably secured to the body it? of the tool, to place its upper and lower seals 69, 70 on opposite sides of the body ports 22, by a threaded coupling mechanism. As specifically disclosed, this coupling mechanism includes a nut 72 mounted on the upper portion of the mandrel 66 and slidably splined thereto by virtue of a longitudinally extending key 73 secured to the mandrel and disposed within a longitudinal keyway 74 in the nut. The nut has a left-hand thread 75 companion to the left-hand thread 12 on the body head, the nut 72 being screwed into the body when the mandrel is to be secured to the well packer. However, the nut is capable of being disposed in an upper position on the mandrel 66, and with a recess 76 in the upper sub defined between the upper portion of the mandrel and a depending sub skirt 77. In moving upwardly into the recess, the coupling nut 72 engages the lower end of a spring 78, moving it upwardly with it until the spring engages the base of the recess 76 and is compressed. The spring '78 facilitates the starting of the threaded connection 75, 12 between the nut 72 and the threaded box in the body. When the mandrel. is inserted. within the body of the tool, the lowermost portion of the nut thread '75 will engage the body thread 12. At this time, the spring 78 is compressed, urging the nut downwardly, so that rotation of the mandrel 66 will effect a threading or feeding of the nut 72 Within the left-hand. threaded box 12 of the body, until the nut has been screwed. into the box to the fullest extent, at which time, the mandrel seals 69, 70 will be disposed on opposite sides of the body ports 22.

Pressure can be built up in the fluid within the tubular string C, mandrel 66, ports 71, 22 and cylinder 13 by closing the central passage 80 through the mandrel 66 below the mandrel ports 71. In the present instance, such closing action occurs as a result of dropping or pumping a ball valve element 81, or the like, through the tubular string C, this ball-valve element moving through the mandrel passage Si) and coming to rest upon a tubular Valve seat 82 secured to a lower tubular mandrel sub 83 by one or more shear screws 84, this sub being threadedly attached to the lower end of the mandrel 66.

Prior to lowering the apparatus A within the well casing B disposed in the well bore, the upper and lower slips 35, 23, packing sleeve 30 and upper and lower expander 31, 26, all occupy their initial positions, in which the slips and packing sleeve are retracted (PEG. 1). At this time, the split stop ring 51 is disposed in the body groove 53 and also within the lower slips 23. The shear pin 57 is intact, holding the trip ring 56 adjacent the stop ring 51, the piston 16 occupying its lower position in the cylinder 13. The setting tool or mandrel 66 is then inserted within the packer, the tripping ball seat 82 being releasably retained in the sub 83 by the one or more shear screws 84. At this time, the tripping ball or ball valve element 81 is not contained within the mandrel. The insertion of the mandrel in the packer body 16 causes the mandrel to swing the flapper valve 62 downwardly about its pivot axis to the open position disclosed in FIG.

*1. The lower end of the nut 72 will engage the uppermost box thread 12, the mandrel then moving downwardly to a further extent within the body and the nut shifting against the spring 7s and moving it upwardly within the recess 76 into engagement with the base of the latter, whereupon the spring will be compressed to exert a downwardly directed force on the nut. The mandrel is then rotated, the spring 78 forcing the nut 72 longitudinally of the body box 12, whereby the nut threads into the box to the fullest extent, such as shown in FIG. 1. When this occurs, the upper and lower mandrel seals 69, 70 are disposed on opposite sides of the body ports 22.

The apparatus A is secured to the lower end of the tubular string C. It is then lowered in the well casing B to the desired setting point. During such lowering, the fluid in the well casing can move upwardly through the mandrel and into the tubing string. When the location in the well casing has been reached at which the well packer is to be anchored in packed-off condition, the tripping ball 81 is dropped into the tubing string C at the top of the hole, from where it is allowed to gravitate or is pumped through the tubing string and through the mandrel passage 80 until it comes to rest on the tubular seat 82, closing the mandrel passage against downward flow of fluid. Pressure is then built up in the fluid in the tubing string and the mandrel, this fluid under pressure passing outwardly through the ports 71, 22 into the cylinder 13 and shifting the annular sleeve 16 upwardly within the annularcylinder. The upper end 59 of the piston 16 first engage the trip ring 56, disrupting the pin 57 and then shifting the trip ring upwardly. The coengaging tapered surfaces 55, 54 on the trip ring and the stop ring 51 causes the split stop ring 51 to be shifted laterally outwardly completely from the body groove 53, this ring then being disposed fully within the lower slips 23. After the stop ring 51 has been released from .the body, the piston engages the lower ends 58 of the lower slips 23. When the pressure in the apparatus increases sufiiciently to overcome the shear strength of the screws holding the lower slips to the lower expander 26, such screws are disrupted'and the piston 16 moves upwardly in the cylinder 13, sliding the lower slips .23 upwardly along the lower expander and radially outwardly into engagement with the wall of the well casing, which is the position illustrated in FIG. 3.

Downweight is now imposed on the tubing string C,

which is transmitted through the upper sub 65 to the body 10 'of the tool. strength of the screws 27 holding the lower expander 26 When the weight exceeds the shear to the body 10, such screws are sheared or disrupted, the upper expander 31 then being moved toward the lower expander, effecting a foreshortening of the packing sleeve and its lateral expansion into engagement with the wall of the well casing B, as well as into firmer engagement with the periphery of the body 10 of the tool. A continuation of the downwardly directed weight or force on the tubing string C and the body It) of the tool then effects a disruption of the shear screws 32 holding the upper expander 31 to the body of the tool, the downward movement of the body being transferred through the ratchet sleeve 46 to the setting sleeve 37, which then disrupts the shear screws 36 holding the upper slips to the upper expander and shifts the upper slips downwardly along the upper expander and radially outwardly into engagement with the wall of the well casing, such condition being disclosed in FIG. 4.

The upper and lower slips 35, 23 and the packing sleeve 30 have now been expanded into engagement with the well casing. However, they have not been set firmly against the well casing. Such action occurs as a result of then taking an upward strain on the tubing string C, which upward strain is transferred to the mandrel 66 and from the latter through the setting nut 72 to the body 10 of the tool. Since the upper slips 35 engage the well casing, the parts externally of the body of the tool cannot move upwardly, the ratchet ring 46 permitting the body to ratchet freely through the setting sleeve 37, which is prevented from moving upwardly by the guide pins 40,

which insure the radial outward movement of the upper slips into engagement with the casing. The body 10 moves upwardly until the cylinder sleeve 14 again engages the lower slips 23, the upward force then being exerted through the lower slips and lower expander 26, packing sleeve 39 and upper expander 31 to the upper slips 35, embedding the latter more firmly in the Wall of the well casing, compressing the packing sleeve 30 to a still further extent, and insuring the greater wedging of the lower slips 23 outwardly into anchoring engagement with the Well casing. Following release of the upward strain on the tubular string, mandrel and body of the tool, the body it? cannot shift downwardly again because of the one-way locking action of the body teeth 44 against the teeth 45 of the ratchet sleeve 46, the ratchet sleeve being prevented from shifting outwardly by the camming action of the coengaging tapered cam elements 47, 48 of the ratchet sleeve 46 and the setting sleeve 37.

The well packer has now been anchored in packed-0E condition within the well casing (FIG. 5). The passage till through the tubing string and mandrel can be cleared by increasing the pressure of the fluid in the tubing string and the mandrel, this fluid under pressure acting downwardly on the ball $1 and the tubular seat 82, and when sufiicient to overcome the shear strength of the screws 84, disrupting the latter, so that the ball and seat are then pumped out of the mandrel 66 of the tool, dropping down into the well bore. A clear passage now exists through the mandrel 66 of the tool, enabling the well production to flow upwardly from the formation through the casing and into the mandrel 66, continuing'on up through the tubular string C-to the top of the well bore.

In order to prevent fluid communication through the body ports 22 between the interior of the mandrel 66 and the cylinder 33, the tubular string is rotated to the right to rotate the nut 72 relative to the body ll of the tool. The key and keyway connection 42, 41 between the body 19 and. the upper expander 31 prevents rotation of the body, the nut 72 feeding upwardly along the mandrel 66 and engaging the spring '78, to move the latter into the recess '76, the nut unthreading completely from the box 12 of the tool and then engaging the uppermost thread of the tool box with its lowermost thread. At this time, the mandrel 66 may be elevated so that the lower mandrel seal 7% is disposed above the body ports 22, to prevent communication between the interior of themandrel and the interior 15 of the cylinder 13. A multiple seal 69, 74B is provided between the mandrel and the inner wall 21 of the body, to prevent leakage therebetween, insuring that the well production will pass upwardly through the mandrel 66 into the tubing string (3, despite the fact that the mandrel has been fully disconnected from the well packer.

At any time that it is desired to remove the tubing string C from the well bore, it need merely be lifted, the mandrel 65 moving back up through the body It) of the tool. When the lower end of the mandrel passes above the valve seat 64, the flapper valve 62. can shift upwardly into engagement therewith to'preclude upward flow of fluid through the well packer.

The inventors claim:

1. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said body to a tubular runningin string extending to the top of the Well bore; an upper expander on said body; normally retracted upper slips engaging said upper expander; a lower expander on said body; normally retracted lower slips engaging said lower expander; a cylinder on said body below said lower slips; said body having a port for feeding fluid under pressure from the running-in string and interior of said body to said cylinder; a piston in said cylinder movable upwardly along said cylinder by fluid pressure in said cylinder to shift said lower slips along said lower expander and outwardly against the well conduit; means on said body movable downwardly therewith. to shift said upper slips along said upper expander and outwardly against the well conduit; and one'way ratchet means releasably connecting said means on said body and said body to prevent downward movement of said body relative to said means on said body and to permit upward movement of said body relative to said. means on said body, whereby downward movement. of said tubular running-in string shifts said body, ratchet means and means on said body downwardly to shift said upper slips along said upper expander.

2. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said body to a tubular running in string extending to the top of the well bore; an upper expander on saidbody; normally retracted upper slips engaging said upper expander; a lower expander on said body; normally retracted lower slips engaging said lower expander; a cylinder on said body below said lower slips; said body having a port for feeding fluid under pressure from the running-in string and interior of said body to said cylinder; normally retracted packing means on said body between said expanders; a piston in said cylinder movable upwardly along said cylinder by fluid pressure in said cylinder to shift said lower slips along the lower expander and outwardly against the well packer; means on said body movable downwardly therewith to expand said packing means against the well conduit and to shift said upper slips along said upper expander and outwardly against the well conduit; and one-way ratchet means releasably connecting said means on said body and said body to prevent downward movement of said body relative to saidmeans on said body and to permit upward movement of said body relative to said means on said body, whereby downward movement of said tubular running-in string shifts said body, ratchet means and means on said body downwardly to expand said pack ng means and shift said upper slips along said up er expander.

3.. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said body to a tubular running-in string extending to the top of the well here; an upper expander on said body; normally retracted upper slips engaging said upper expander; a lower expander on said body; normally retracted lower slips engaging said lower expander; an annular cylinder on said body' below said lower slips; said body having a port for feeding fluid under pressure from the running-in string and interior of said body to said annular cylinder; an annular piston in said cylinder movable upwardly along said cylinder by fluid pressure in said cylinder to shift said lower slips along said lower expander and outwardly against the well conduit; means on said body movable downwardly therewith to shift said upper slips along said upper expander and outwardly against the well conduit; and oneway ratchet means releasably connecting said means on said body and said body to prevent downward movement of i said body relative to said means on said body and to permit upward movement of said body relative to said means on said body, whereby downward movement of said tubular running-in string shifts said body, ratchet means and means on said body downwardly to shift said upper slips along said upper expander.

4. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said body to a tubular running-in string extending to the top of the well bore; upper and lower normally retracted slip means for anchoring said body to the well conduit against both upward and downward movement; hydraulically operable means responsive to fluid pressure within the running-in string and s id body for shifting said lower slip means upwardly of said body and outwardly against the well conduit; means movable downwardly with said body for shifting said upper slip -meaus downwardly and outwardly a ainst the well conduit; said means movable downwardly with said body,

including a radially slidable connection with said upper slip means, to prevent relative longitudinal movement in both. directions between said last-mentioned means and upper slip means, while. permitting radial movement of said upper slip means; and one-way ratchet means releasabl-y connecting said means for shifting said upper slip means and said body to prevent downward movement of said body relative to said means for shifting said upper slip means and to permit upward movement of said body relative to said means for shifting said upper slip means, whereby downward movement of said tubular running-in string shifts said body, ratchet means and cans for shifting said upper slip means downwardly to shift said upper slip means against the well conduit.

5. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said. body to a tubular running-in string. extending tothe top of the well bore; an upper expander on said body; normally retracted upper slips engaging said upper expander; 21 lower expander on said body; normally retracted lower slips engaging said lower expander; a cylinder on said body below said lower slips; said body having a port for feeding fluid under pressure from the running-in string and interior of said body to said cylinder; a piston in said cylinder movable upwardly along said cylinder by fluid pressure in said cylinder to shift said lower slips along said lower expander and outwardly againstthe well conduit; means on said body movable downwardly therewith to shift said upper slips along said upper expander and outwardly against the well conduit; said means movable downwardly with said body including a radially slidable connection with said upper slips to prevent relative longitudinal movement in both directions between said means movable downwardly with said body and upper slips while permitting radial movement of said upper slips; and one-way ratchet means releasably connecting said means on said body and said body to prevent downward movement of said body relative to said means on said body and to permit upward movement of said body relative to said means on said body, whereby downward movement of said tubular running-in string shifts said body, ratchet means and means on said body downwardly to shift said upper slips along said upper expander;

6. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having means thereon for connecting said body to a tubular running-in string extending to the top of the well bore; an upper expander on said body; normally retracted upper slips engaging said upper expander; a lower expander on said body; normally retracted lower slips engaging said lower expander; a cylinder on said body below said lower slips; said body having a port for feeding fluid under pressure from the running-in string and interior of said body to said cylinder; a piston in said cylinder movable upwardly along said cylinder by fluid pressure in said cylinder to shift said lower slips along said lower expander and outwardly against the well conduit; a setting sleeve on said body above said upper slips; one-way lock means between said body and setting sleeve permitting upward movement of said body relative to said setting sleeve but preventing downward movement of said body relative to said setting sleeve, whereby downward movement of said tubular running-in string and body is transferred through said lock means to said setting sleeve to shift said upper slips downwardly along said upper expander and outwardly against the well conduit; and a radially slidable connection between said upper slips and setting sleeve to prevent relative longitudinal movement in both directions between said setting sleeve and upper slips while permitting said upper slips to move radially outward of said setting sleeve.

7. In a well tool adapted to be set in a well conduit disposed in a well bore: body means; normally retracted segmental slips on said body means adapted to be expanded against the well conduit; a stop member engaging said body means and segmental slips to prevent relative longitudinal movement therebetween; and means for shifting said stop member laterally from engagement with one of said means to permit relative longitudinal movement between said body means and slips.

8. In a well tool adapted to be set in a well conduit disposed in a well bore: a body; normally retracted segmental slips on said body adapted to be expanded against the well conduit; a stop member engaging said body and segmental slips to prevent relative longitudinal movement therebetween; and means for shifting said stop member laterally from engagement with said body to permit relative longitudinal movement between said body and slips.

9. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having a circumferential groove; normally retracted segmental slips on said body having a circumferential groove and adapted to be expanded against the well conduit; a stop ring in said grooves to prevent relative longitudinal movement between said body and slips; and means for shifting said stop ring from one of said grooves to permit relative longitudinal movement between said body and slips.

10. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having a circumferential groove; normally retracted means on said body having a circumferential groove and adapted to be expanded against the well conduit; means for expanding said normally retracted means outwardly into engagement with the well conduit; a stop ring in said grooves to prevent relative longitudinal movement between said body and normally retracted means; and a trip ring on said body movable therealong to engage and shift said stop ring from one of said grooves to permit relative longitudinal movement between said body and normally retracted means.

11. In a well tool adapted to be set in a well conduit disposed in a well bore: a body having a circumferential groove; normally retracted means on said body having a circumferential groove and adapted to be expanded against the well conduit; means for expanding said normally retracted means outwardly into engagement with the well conduit; a stop ring in said grooves to prevent relative longitudinal movement between said body and normally retracted means; and a trip ring on said body movable therealong; one of said rings having a tapered surface engaged by said other ring, when said trip ring moves along said body, to expand said stop ring from said body groove and permit relative longitudinal movement between said body and normally retracted means.

12. In well apparatus to be disposed in a well conduit located in a well bore: a tubular body; normally retracted means on said body; hydraulically operable means on said body for expanding said normally retracted means against the well conduit; a tubular mandrel connectible to a tubular string and adapted to be disposed in said body; said body and mandrel having ports for feeding fluid under pressure from the interior of said mandrel to said hydraulically operable means; said body having a threaded box; a threaded nut slidably splined on said mandrel and meshing with said threaded box; said nut being adapted to move upwardly of said mandrel and completely from said box; and seal means between and engaging said mandrel and body preventing fluid communication between said mandrel ports and body ports following unthreading of said nut from said threaded box.

13. In well apparatus to be disposed in a well conduit located in a well bore: a tubular body; normally retracted means on said body; hydraulically operable means on said body for expanding said normally retracted means against the well conduit; a tubular mandrel connectible to a tubular string and adapted to be disposed in said soonest body; said body and mandrel having ports forfeeding fluid under pressure from the interior of said mandrel-to said hydraulically operable means; said body having a threaded box; a threaded nut slidably splined on said mandrel and meshing with said threaded box; said nut being adapted to move upwardly of said mandrel and completely from said box; spring means on said mandrel engageable with said nut to yieldably urge said nut down-' wardly of said mandrel and box; and seal means between and engaging said mandrel and body preventing fluid communication between said mandrel ports and body ports following unthreading of said nut from said threaded box.

14. In a well tool adapted to be set in a well conduit disposed in a well bore: body means; an expander on said body means; normally retracted segmental slips on said body shiftable longitudinally along said expander for outward expansion against the well conduit; a stop member engaging said body means and segmental slips to prevent relative longitudinal movement therebetween; and means movable longitudinally along the exterior of said body means for shifting said stop member laterally from engagement with one of said means to permit relative longitudinal movement between said body means and slips; said shifting means including means for moving said slips and expander longitudinally relative to each other to expand said slips outwardly against the well conduit.

15. In a well tool adapted to be set in a well conduit disposed in a well bore: body means; an expander on said body means; normally retracted segmental slips on said body shiftable longitudinally along said expander for outward expansion against the well conduit; a stop mem ber engaging said body means and segmental slips to prevent relative longitudinal movement therebetween; and means movable longitudinally along the exterior of said body means for shifting said stop means laterally from engagement with said body means to permit relative longitudinal movement between said body means and slips; said shifting means including means for moving said slips longitudinally along said expander to expand said slips outwardly against the well conduit.

16. In well apparatus to be disposed in a well conduit located in a well bore: a tubular body; normally retracted means on said body; hydraulically operable means on said body for expanding said normally retracted means against the well conduit; a tubular mandrel connectible to a tubular string and adapted to be disposed in said body; said body and mandrel having ports for feeding fluid under pressure from the interior of said mandrel to said hydraulically operable means; said body having a threaded box; a threaded nut slidably splined on said mandrel and meshing with said threaded box; said nut being adapted to move upwardly of said mandrel and completely from said box; and seal means on said mandrel below said mandrel ports sealingly engaging said body above said body ports following unthreading of said nut from said threaded box to prevent fluid communication between said mandrel and body ports.

References Cited in the file of this patent UNITED STATES PATENTS 1,947,262 Howard Feb. 13, 1934 2,019,885 Black Nov. 5, 1935 2,040,155 Shoemaker May 12, 1936 2,092,048 Brown Sept. 7, 1937 2,111,956 Baldwin Mar. 22, 1938 2,159,640 Strom May 23, 1939 2,189,702 Burt Feb. 6, 1940 2,192,336 Thornhill Mar. 5, 1940* 7 2,270,647 Church Jan. 20, 1942 2,315,921 Baker Apr. 6, 1943 2,368,401 Baker Jan. 30, 1945- (Other references on foliowing page) .1; 12 UNITED STATES PATENTS 7 2 ,695,064 Raggn at al. N9v.2, 1954 M51891 Baker Apr. 19, 1949 2,707,998 Baker May 10, 1 5 2,479,950 Osborn Aug. 23, 1949 2 7 ,2 2 B lm: et aln----- 1.956 2,578,900 Ragan Dec. 18, 1951 2,815,081 Chm ch ..V .I Dec. 3, 1957 2,624,412 Ragan Y,.V Jan. 6,1 3 5 2,823,754 Ault Feb. 18, 1958 

